1. Field
The present invention relates to a hinge device, as well as to an automatic document feeder having the hinge device, to a scanning unit having the same, and to an image forming apparatus having the same.
2. Related Art
In a multifunction machine having a printing function, a scanning function, and the like, a document platen is reclosable with respect to a main body; and the document platen and the main body are generally connected by means of a hinge. As an example of this configuration, JP-A-2000-129993 discloses a hinge device including an attachment member attached to a main body, and a movable member pivotally attached to the attachment member via a pair of hinges. More specifically, the hinge device has teeth disposed around the pair of hinges; and a pair of fixed racks which extend in the horizontal direction and which are to be engaged with the teeth. According to this configuration, when the movable member is pivoted clockwise, the pair of hinges move to the left. Accordingly, the distance between the hinges and a wall behind the multifunction machine increases, thereby enabling a housing 12 to be opened wide without causing the housing 12 to bump against the wall.
In the configuration disclosed in JP-A-2000-129993, a pivot center of a hinge device is generally formed at an inner side in relation to a back face of a multifunction machine. Therefore, in the configuration disclosed in JP-A-2000-129993, as illustrated in FIG. 3 of the same, a notch is formed in a back end of a document platen, thereby preventing the back end from interfering with an upper face of the main body at the time of opening/closing of the document platen. However, such a configuration involves a problem that the notch must be formed in the document platen; as well as a problem that a gap is created between the notch and the upper face of the main body, which is not preferable in view of external appearance.